Vascular clamps and surgical retractors with directional filaments for tissue engagement

ABSTRACT

Surgical clamps, tissue retractors and surgical stabilizers are disclosed having gripping surfaces from which extend resilient filaments. The distal ends of some of the resilient filaments abut against engaged vessels, tissues or organs to restrict movement of the vessels, tissue or organs relative to the gripping surfaces. In the preferred embodiment, the resilient filaments are arranged in rows and oriented at particular angles relative to the gripping surfaces. Methods of applying resilient filaments to pads for attachment to a surgical clamp, tissue retractor or surgical stabilizer are also disclosed.

This application is a continuation of U.S. application Ser. No.09/337,115 filed on Jun. 21, 1999, which is a continuation-in-part ofU.S. application Ser. No. 08/993,076 filed Dec. 18, 1997 now U.S. Pat.No. 6,007,552, which is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to surgical instruments foroccluding a vessel or other tubular structure, for grasping andretaining other body tissue, for retracting tissue at a surgicalincision site, or for stabilizing tissue or bodily organs within asurgical incision site. More particularly, the invention relates tosurgical instruments such as surgical clamps, surgical retractors orsurgical stabilizers that include resilient filaments that abut againsta vessel, tissue or organ to resist movement of the vessel, tissue ororgan relative to the instrument. The invention further relates tomethods of manufacturing clamp pads or members for attachment to suchinstruments that include such resilient filaments.

2. Description of the Related Art

Instruments for occluding blood vessels during surgery, such asconventional metal or rigid surgical clamps or clips, are well known.However, such instruments are known to cause trauma to the clampedvessel at the clamping site. A number of atraumatic instruments havebeen developed for reducing or eliminating the trauma to a vessel duringocclusion of the vessel. U.S. Pat. No. 3,993,076 to Fogarty, et al.describes a device whereby a vessel is occluded by using a resilienttape to press a vessel against a resilient pad. However, this devicesuffers from the disadvantage that it slips easily. For example, thepulsations of an occluded artery can tend to force the device off of itsclamped position on the occluded artery. Conventional surgical clampshave also been adapted to include jaw surfaces containing resilientmembers or pads. These devices likewise are prone to slipping off of theclamped vessel. This can be especially problematic in situations where,due to obstructions, a vessel has been clamped with only the distal tipsof the clamp jaws. In such situations, the vessel can be especiallyprone to slipping in the direction of the distal tips.

Other attempts have been made to atraumatically occlude a vessel in asecure fashion. U.S. Pat. No. 3,746,002 to Haller describes a vascularclamp with resilient gripping members located on the jaws. A pluralityof pin members are embedded within the gripping members, the pin membersof a length such that when a vessel is clamped between the members, theresilient material deflects to accommodate the vessel, exposing the pinmembers which grippingly engage the outer layer of the vessel, thussecuring the vessel to the gripping member. While the Haller device isless traumatic to a vessel than other occlusion devices, it neverthelesshas the disadvantage of traumatizing the outer layer of the vessel.

U.S. Pat. No. 4,821,719 to Fogarty describes a vascular clamp devicecontaining resilient pads with Velcro-like hooks. The hooks interactwith the external adventitial layer of the vessel forming acohesive-adhesive relationship with the vessel similar to the bonding ofVelcro materials. While this device offers a less traumatic way toocclude a vessel, the cohesive-adhesive nature of the bond can result inthe removal of some of the adventitial layer of the vessel whendisengaging the device.

There is thus a need for a surgical clamp which atraumatically occludesvessels while avoiding the disadvantages previously associated withexisting surgical clamps or occlusion devices.

Likewise, conventional tissue retractors are well known which retracttissue at a surgical incision site to provide a surgeon visual andmechanical access to the interior of a patient's body. These tissueretractors employ rigid gripping members, usually of metal, to grip,retract, and retain all forms of body tissue, e.g., bone, skin, fat, ormuscle, at the incision site. The disadvantages of such retractors aretwo-fold. First, the rigid gripping members, due to their rigidity,cause trauma to the retained tissues. Second, the gripping members aregenerally prone to slippage, both laterally, along the sides of theincision, and upwardly out of the incision and away from the patient'sbody.

Thus, there is also a need for a surgical retractor that atraumatically,yet securely, retracts and retains tissue at a surgical incision site.

Other surgical instruments or devices are known that provide formechanical immobilization and stabilization of tissue or organs within asurgical incision site. These instruments or devices, known asstabilizers, will immobilize, stabilize, or otherwise restrain tissue ororgans by exerting pressure against a tissue or organ to hold the tissueor organ in place, aiding a surgeon performing operations on the tissueor organ. Such stabilizers have particular use in minimally invasivecoronary surgery procedures. For example, coronary artery stabilizershave been used to immobilize a beating heart in order to performcoronary grafting. These stabilizers achieve immobilization largely bylocal myocardial compression from direct pressure applied by thestabilizer on either side of the grafted artery. These stabilizers comein a variety of shapes, including open foot-shaped devices, and rigidcircle or rectangular shapes, and may be either hand held, or attachedto an incisional retractor located at the incision site. Another suchstabilizer device consists of a system having two fixed handles havingsuction cups that are positioned on either side of the vessel.

Given the amount of pressure transferred to the myocardium during theuse of these stabilizers, there is a danger that the contact surfaces ofthese stabilizer devices will traumatize the myocardial tissue. Inaddition, the forces exerted by the immobilized but still beating heartcan lead to a shift in alignment of the stabilizer, which can disruptthe grafting procedure. Thus, there is a need for stabilizers thatatraumatically immobilize a tissue or body organ, such as the heart, andyet at the same time provide improved traction to maintain the positionof the immobilized tissue or organ.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide surgicalinstruments, including surgical clamps or other occlusion devices,surgical retractors, or surgical stabilizers having gripping surfacesand an array of resilient filaments extending at acute angles relativeto the surface for engagement with vessels, tissue, or organs. Thefilaments terminate in free distal ends that abut against the engagedvessel, tissue or organ to resist and restrict movement of the engagedvessel, tissue or organ in a direction opposed to the orientation of thefilaments. The filaments themselves can also be resiliently flexible soas to cushion the engaged vessel, tissue or organ.

In the case of a surgical clamp according to the present invention, thefilaments are located on opposing jaws of a surgical clamp. When thejaws are moved toward one another to engage a vessel, some of thefilaments, based on their angle of orientation in relation to thevessel, will abut against the vessel and impart a resistive forceagainst the vessel along the direction of the filament. When the jaws ofthe surgical clamp are partially or fully engaged with the vessel,filaments of the lower jaw push or lever the vessel upward toward theupper jaw, while at the same time filaments of the upper jaw push orlever the vessel downward toward the lower jaw. This levering action ofthe filaments secures against movement of the vessel in a directiongenerally opposed to the orientation of particular filaments.

In one embodiment of the invention, the filaments can extend directlyfrom the surface, which itself can be resiliently flexible. In thisembodiment, when the jaws are moved toward one another to engage avessel, some of the filaments, based on their angle of orientation inrelation to the vessel, will be pressed flat against the surface whichwill itself deflect to accommodate the vessel in atraumatic fashion. Inan alternative embodiment, the filaments can extend from along the sidesof the resilient surface and the distal ends of the filaments canterminate at positions even with, above, or below the level of thesurface. In this embodiment, the surface can deflect to atraumaticallyengage the vessel while the filaments are likewise engaging the vesseland resisting movement of the vessel in a direction opposed to theorientation of the filaments. Where the distal ends of the filamentsterminate at a position below the level of the surface, the surface willdeflect to a position where both the surface and the filaments willengage the vessel.

In another embodiment of the invention, the filaments can be oriented asdiscussed above to resist movement of the vessel in the direction of thedistal ends of the surgical clamp jaws. Such an orientation isespecially advantageous where, due to obstructions, a surgeon can onlyaccess and clamp a vessel with the distal tips of the surgical clampjaws. With a conventional clamp, the vessel can slip from the clamp inthe direction of the distal tips. In the above embodiment of the presentinvention, however, slippage of the vessel will favor the direction backtoward the proximal ends of the surgical clamp jaws, thereby retainingthe vessel in a clamped condition.

In another embodiment of the invention, the filaments of the upper andlower jaws of the surgical clamp are oriented to resist movement of aclamped vessel towards either the distal or the proximal ends of thejaws. The filaments can also be oriented to resist movement of a clampedvessel in a direction perpendicular to the jaws.

A surgical retractor according to the present invention likewise usesresilient surfaces with resilient filaments that engage and retracttissue. When the resilient member, or base member, containing theresilient filaments engages tissue at an incision site, the tips of someof the filaments, again based on the angle of orientation of thesefilaments in relation to the tissue being retracted, will abut againstthe tissue and impart a resistive force against the tissue along thedirection of the filament. In one embodiment of the invention, thefilaments can be oriented to resist movement of the retracted tissuerelative to the base member in a lateral direction along the sides ofthe incision and in an upwardly direction away from the patient's body.

A surgical stabilizer according to the present invention also includessurfaces having resilient filaments that engage and restrain tissue ororgans. When the resilient filaments engage the target tissue or organ,the tips of some of the filaments, again based on the angle oforientation of these filaments in relation to the tissue or organ beingrestrained, will abut against the tissue or organ and impart a resistiveforce against the tissue or organ along the direction of the filament.In one embodiment of the invention, the stabilizer can have one or morestabilizing members or arms that engage the target tissue or organ. Theresilient filaments of each engaging arm can be oriented to resistrelative movement of the restrained tissue or organ along the arm lengthand/or transverse to the arm length.

It is a further object of the present invention to provide attachablepads or members for a surgical clamp or other occlusion device, surgicalretractor, or surgical stabilizer that contain gripping surfaces andarrays of filaments extending at acute angles relative to the surfacesfor engagement with vessels or tissue. Again, these filaments are suchthat when the particular device is engaged with a vessel or othertissue, the filaments abut against the vessel or tissue to resist andrestrict movement of the vessel or tissue in a direction opposed to theorientation of the filaments. The filaments can extend directly from thesurface of the pad or can extend from along the sides of pad. For padshaving filaments extending directly from the pad surface, preferably thepad will include a resilient or elastomeric cushion having portions ofthe filaments embedded in the cushion itself. Optimally, the filamentsare resiliently deflectable and the cushion will be softer and moreeasily deflected than the filaments. The characteristics of the cushionand the embedded filaments are such that the cushion and filaments worktogether to achieve a synergistic effect. The portion of the cushioncontaining the embedded filaments forms a clamping region of thecushion. The embedded filaments provide structural support to theclamping region, by reinforcing and stabilizing the region againstexcessive deformation, especially lateral deformation, when the pad isunder a clamping load. The clamping region in turn stabilizes andorients the filaments at the desired angles relative to the pad surfaceto provide directional resistance against movement of engaged vessels ortissue. The clamping region performs this orientation function prior toand during the application of a clamping load to the pad. When a load isapplied to the pad, the filaments and the cushion are deflected, but theclamping region stabilizes the filaments against excessive deformationand maintains the desired orientation of the filaments. The clampingregion continues to perform this function as the load is released fromthe pad and the deflected filaments and cushion return to their originalpre-loaded positions.

Methods of manufacturing the attachable pads or members of the presentinvention are also provided. According to one method, a tubular orcylindrical sleeve of woven resilient filaments is provided and a padwith a gripping surface is extended through the sleeve. The sleeve issecured to the pad opposite the gripping surface and the sleeve is thencut longitudinally along the gripping surface, releasing the resilientfilaments to extend at acute angles relative to the gripping surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a surgical clamp according to thepresent invention in a position to engage a vessel;

FIG. 2 is a perspective view of the surgical clamp of FIG. 1 engagedwith and occluding a vessel;

FIG. 3 is a perspective view of a surgical clamp pad capable ofattachment to the jaw of a surgical clamp, with a surface containingresilient filaments according to the present invention;

FIG. 4 is an enlarged perspective view of the surgical clamp pad of FIG.3, with parts broken away;

FIG. 5 is an end view of the surgical clamp pad of FIG. 3;

FIG. 6 is a side view of opposed jaws of a surgical clamp with attachedclamp pads of FIG. 3 which include opposed surfaces containing resilientfilaments, positioned to engage a vessel;

FIG. 7 is a side view according to FIG. 6 where the opposed surfacescontaining resilient filaments have engaged the vessel, and the vesselis partially occluded;

FIG. 8 is a side view according to FIG. 7 where the opposed surfacescontaining resilient filaments have fully engaged the vessel and thevessel is occluded;

FIG. 9A is an enlarged side view of FIG. 8 showing the resilientfilaments of the lower opposed surface engaged with the vessel ingreater detail;

FIG. 9B is an enlarged side view similar to FIG. 9A showing theresilient filaments of the upper opposed surface in a differentorientation;

FIG. 10 is a top view of a pad constructed according to the presentinvention having a different arrangement of resilient filaments, withpart of the pad broken away;

FIG. 11 is a side view of the FIG. 10 pad;

FIG. 12 is an end view of the FIG. 10 pad;

FIG. 13 is top view similar to FIG. 10 of a pad constructed according tothe present invention having yet another arrangement of resilientfilaments, with part of the pad broken away;

FIG. 14 is a side view of the FIG. 13 pad;

FIG. 15 is an end view of the FIG. 13 pad;

FIG. 16 is a perspective view of a surgical clamp pad according to thepresent invention with resilient filaments extending from along thesides of the pad;

FIG. 17 is a side view of the FIG. 16 pad;

FIG. 18A is a cross-sectional view of the pad shown in FIG. 17 takenalong line 18A—18A of FIG. 17;

FIGS. 18B-18D are cross-sectional views of pads according to the presentinvention showing different configurations of resilient filaments;

FIG. 19 is a side view of opposed jaws of a surgical clamp with attachedclamp pads of FIG. 16 which include opposed surfaces and resilientfilaments, and where the surfaces and filaments have engaged the vesseland the vessel is partially occluded;

FIG. 20 is a perspective view of a surgical clamp pad with resilientfilaments according to the present invention;

FIG. 21 is a side view of the FIG. 20 pad;

FIG. 22 is a cross-sectional view of the pad shown in FIG. 21 takenalong line 22—22 of FIG. 21;

FIG. 23 is a side view of opposed jaws of a surgical clamp with attachedclamp pads of FIG. 20 which include opposed surfaces and resilientfilaments, and where the surfaces and filaments have engaged the vesseland the vessel is partially occluded;

FIG. 24 is an exploded perspective view illustrating resilient filamentsaccording to the present invention secured along individual spines;

FIG. 25 is a perspective view illustrating the resilient filaments andspines of FIG. 24 in an assembled nested condition;

FIG. 26 is a perspective view illustrating the assembled resilientfilaments and spines of FIG. 25 embedded in a resilient cushion;

FIG. 27 is a top view of a pad constructed according to the presentinvention having yet another arrangement of resilient filaments, withparts of the pad broken away;

FIG. 28 is a perspective view of the pad shown in FIG. 27;

FIG. 29 is a perspective view of a surgical retractor according to thepresent invention positioned above a surgical incision site;

FIG. 30 is a side view of a base member of the surgical retractor shownin FIG. 29;

FIG. 31 is a cross-sectional view of the base member shown in FIG. 30,taken on line 31—31 of FIG. 30;

FIGS. 32A-32E are side views illustrating different configurations ofresilient filaments which may be used in the present invention;

FIGS. 33A-33E are end views of the resilient filaments of FIGS. 32A-32E,respectively.

FIG. 34A is a perspective view illustrating a tubular sleeve ofresilient filaments and a pad prior to assembly according to the presentinvention;

FIG. 34B is an end view of the sleeve and pad of FIG. 34A;

FIG. 35A is a perspective view of the sleeve and pad of FIG. 34A withthe sleeve in a tightened condition against the pad;

FIG. 35B is a cross-sectional view of the sleeve and pad shown in FIG.35A, taken on line 35B—35B of FIG. 35A;

FIG. 36A is a perspective view of the sleeve and pad assembly of FIG.35A, secured to a base member;

FIG. 36B is a cross-sectional view of the assembly of FIG. 36A, taken online 36B—36B of FIG. 36A;

FIG. 37 is a perspective view of the assembly of FIG. 36A showing theremoval of excess portions of the sleeve;

FIG. 38A is a perspective view of the assembly of FIG. 37 showing thesleeve being cut longitudinally along the pad;

FIG. 38B is a perspective view of the assembly of FIG. 38A showing thesleeve completely cut longitudinally along the pad and the resilientfilaments of the sleeve extending upward from the pad surface, forming apad having resilient filaments according to the present invention;

FIG. 38C is an end view of the pad shown in FIG. 38B;

FIG. 38D is an end view of a pad according to the present inventionshowing a different configuration of resilient filaments;

FIG. 39 is a perspective view of another surgical retractor according tothe present invention;

FIG. 40 is an enlarged side view of the surgical retractor of FIG. 39with parts broken away;

FIG. 41 is a perspective view of yet another surgical retractoraccording to the present invention;

FIG. 42 is an enlarged side view of the surgical retractor of FIG. 41with parts broken away;

FIG. 43 is a perspective view of a surgical stabilizer according to thepresent invention;

FIG. 44 is an enlarged side view of the surgical stabilizer of FIG. 43with parts broken away; and

FIG. 45 is a perspective view of the surgical stabilizer of FIG. 43secured to a rib spreader and positioned within an incision site wherethe stabilizer has engaged and is stabilizing a heart.

DETAILED DESCRIPTION OF THE INVENTION Surgical Clamps and Clamp Pads

FIG. 1 is a surgical clamp comprising a pair of opposed jaws 22 and 24and handles 10 and 12 hinged together by pin 14. The handles 10 and 12terminate in finger and thumb rings 2 and 4 that provide for manualoperation of the jaws by a surgeon. Interlocking pawl 6 and ratchetteeth 8 are provided on handles 10 and 12, respectively, to secure jaws22 and 24 in an adjusted clamped position with a vessel V. In FIG. 1,opposed jaws 22 and 24 are positioned to engage vessel V. The opposedjaws 22 and 24 include opposed pads 32, 32 attached to members 30, 30,which are in turn detachably secured to opposed jaws 22 and 24.

FIG. 2 shows the surgical clamp with opposed jaws 22 and 24 in anadjusted clamped position. The opposed pads 32,32 clamp vessel V,thereby causing occlusion of vessel V. Interlocking ratchet teeth 8 areengaged with interlocking pawl 6 to secure the opposed jaws in theclamped position.

An embodiment of the pad 32 and attaching member 30, is depicted inFIGS. 3 and 4. The pad 32 includes resilient filaments 40 for resistingmovement of an occluded vessel relative to the pad 32. As FIGS. 3 and 4depict, the resilient filaments 40 extend from the pad 32 at acuteangles relative to the surface of the pad 32. Any acute angle relativeto the surface will operate to resist relative movement of an occludedvessel. The preferred angle is 45 degrees relative to the surface.

The resilient filaments 40 are comprised of a durable yet flexiblematerial, such as nylon or polyester or polypropylene. The filamentscannot be so rigid that they puncture the occluded vessel, but they mustbe of a strength and resiliency such that they resist a force in adirection opposed to the orientation of the filaments. The effectivelength of the filaments will depend on the length to diameter ratio ofthe filaments. Filaments that are too short and wide and too rigid maypuncture the vessel, whereas filaments too long and narrow may fold overupon themselves when a force is applied and will be unable to restrictrelative movement of the vessel. The preferred length of the filamentsis 0.030 to 0.075 inches, most preferably 0.060 inches. The preferreddiameter of the filaments is 0.005 to 0.012 inches, preferably 0.007inches. Wider filaments may be used, provided they are sufficientlyflexible. The ends or tips of the filaments themselves can comprise avariety of shapes, as depicted in FIGS. 24 and 25. For example, filament101 has a rounded tip, filament 102 has an angled-cut tip, filament 103has a blunt-cut tip, filament 104 has a pointed tip, and filament 105has a semi-rounded tip. Also, the filaments can be cylindrical 101-103,semi-cylindrical 105, or contain three sides 104 or more. The preferredfilament is cylindrical with a rounded tip, as exemplified by filament101. The pad 32 is itself comprised of a resilient material, preferablysilicone. The most preferred composition of the pad 32 is two partsilicone of less than a 20 durometer, liquid injection moldable (GE6040) or a silicone foam such as GE RTF762.

Member 30 provides a rigid backing for pad 32 and means for attachmentof pad 32 to opposed jaws 22 and 24. The member 30 can be made of a hardplastic, such as polycarbonate, or of metal. As depicted in FIGS. 5 and6, a means for attaching pad 32 to an opposed jaw 22 or 24 can comprisea pair of protrusions 52 on member 30 detachably coupled to recesses 50on the jaw.

The operation of one embodiment of the invention is depicted in FIGS. 6,7 and 8. FIG. 6 illustrates upper and lower jaws 22 and 24, opposedmembers 30, 30, and opposed pads 32, 32 with resilient filaments 40 in aposition to engage and occlude vessel V. FIG. 7 illustrates the abovecomponents in partial engagement with vessel V. As depicted in FIG. 7,the resilient members 32, 32 have deflected to accommodate the shape ofvessel V, thereby minimizing trauma to vessel V. FIG. 8 shows the abovecomponents in complete engagement with vessel V causing occlusion ofvessel V. Some of the resilient filaments have been pressed flat alongthe resilient members 32, 32 due to the angle at which the vessel Vengages those filaments. Other resilient filaments remain generallyoriented along an acute angle relative to the pads 32, 32 and abutvessel V. The abutment of some of the resilient filaments against thevessel V creates a resistive force against movement of the vessel V in adirection opposed to the orientation of the abutting filament orfilaments. This resistive force assists in securing vessel V againstmovement relative to pads 32, 32 and opposed jaws 22 and 24.

In the embodiment illustrated in FIGS. 8 and 9A, the resilient filaments40 are oriented such that the filaments on the lower pad 32 that abutvessel V will impart a resistive force upward, thereby pushing orlevering the vessel V upward into the upper pad 32 in a direction alongthe general direction of orientation of resilient filaments. Theresilient filaments on the upper pad 32 that abut the vessel V willimpart a downward resistive force along the general direction oforientation of those particular resilient filaments. In combination, theembodiment as shown in FIG. 8 will resist movement of the occludedvessel V in one lateral direction relative to the opposed jaws 22 and 24while permitting lateral movement of the occluded vessel V in theopposite lateral direction relative to the opposed jaws 22 and 24. Inthe preferred embodiment, lateral movement of the occluded vessel V willbe restricted toward the distal ends of the opposed jaws 22 and 24.

In another embodiment, as depicted in FIG. 9B, the orientation of theresilient filaments of the upper opposed pad 32 can be reversed fromthat of FIG. 8 such that the resistive force resulting from thefilaments on one jaw abutting the vessel restricts lateral movement ofthe vessel V in one lateral direction relative to opposed pads 32, 32,while the resistive force resulting from the filaments on the other jawabutting the vessel restricts lateral movement of the vessel V in theopposite lateral direction relative to opposed pads 32, 32.

The resilient filaments can be arranged in one or more rows, andoriented in one or more directions. FIGS. 10-12 depict an embodiment ofa particular arrangement of resilient filaments 43-45 extending from thepad 32 arranged in three distinct rows and oriented in three separatedirections. The surface of pad 32 defines a plane (surface plane)containing two axes, an axis X running the length of the pad(longitudinal axis), and an axis Y oriented perpendicular to axis X(perpendicular axis). A third axis Z intersects the plane in anorientation normal to the plane (normal axis). In this embodiment, onerow of resilient filaments, comprised of resilient filaments 44, isarranged in a row along longitudinal axis X, and the filaments of thisrow are oriented at an acute angle C from the surface of the pad 32 in aplane defined by longitudinal axis X and normal axis Z, and at an angleD from the surface in a plane defined by perpendicular axis Y and normalaxis Z. A second row of resilient filaments, comprised of filaments 43,is arranged along an axis parallel to longitudinal axis X, and thefilaments of this row are oriented at an angle A1 from longitudinal axisX in the surface plane, at an angle B from the surface of the pad 32 ina plane defined by longitudinal axis X and normal axis Z, and at anacute angle E1 from the surface in a plane defined by perpendicular axisY and normal axis Z. A third set of resilient filaments, comprised offilaments 45, is likewise arranged along an axis parallel tolongitudinal axis X, and the filaments of this row are oriented at anangle A2 from longitudinal axis X in the surface plane, and in adirection generally opposed to the direction of the filaments of thesecond row with respect to this plane, at an angle B from the surface ofthe pad 32 in a plane defined by longitudinal axis X and normal axis Z,and at an acute angle E2 from the surface in a plane defined byperpendicular axis Y and normal axis Z. This arrangement of resilientfilaments, when engaged with a vessel, will resist movement of thevessel relative to the pad 32 in either direction along perpendicularaxis Y, and will also resist movement of the vessel relative to the pad32 in one of two directions along longitudinal axis X.

In the preferred embodiment, the angles A1, A2, B and D areapproximately 90 degrees while the angles C, E1 and E2 are between 30 to60 degrees, most preferably approximately 45 degrees. The number ofresilient filaments per row can be between 8 and 32, and is preferably16. Also, it is preferable, though not necessary, that the filamentsterminate at the same height L relative to the surface of the pad 32.

An alternative arrangement of filaments is depicted in FIGS. 13-15. Inthis embodiment, resilient filaments extending from pad 32 (having asurface plane and longitudinal, perpendicular, and normal axes, X, Y andZ, as described above for FIGS. 10-12) are arranged in two distinct rowsand are oriented in two separate directions. A first row of resilientfilaments, comprised of resilient filaments 46, is arranged along anaxis parallel to longitudinal axis X, and the filaments of this row areoriented at an acute angle F1 from longitudinal axis X in the surfaceplane, at an acute angle G from the surface of pad 32 in a plane definedby longitudinal axis X and normal axis Z, and at an acute angle H1 fromthe surface in a plane defined by perpendicular axis Y and normal axisZ. A second row of resilient filaments, comprised of resilient filaments47, is likewise arranged along an axis parallel to longitudinal axis X,and the filaments of this row are oriented at an acute angle F2 fromlongitudinal axis X in the surface plane, at an acute angle G from thesurface of the pad 32 in a plane defined by longitudinal axis X andnormal axis Z, and at an acute angle H2 from the surface in a planedefined by perpendicular axis Y and normal axis Z. The sum of acuteangles F1 and F2 is less than 180 degrees. This arrangement of resilientfilaments, when engaged with a vessel, will resist movement of thevessel relative to the pad 32 in either direction along perpendicularaxis Y, and will also resist movement of the vessel relative to the pad32 in one of two directions along longitudinal axis X.

In the preferred embodiment, the angles F1, F2, G, H1 and H2 are between30 to 60 degrees, most preferably approximately 45 degrees. The numberof resilient filaments per row can be between 12 and 48, and ispreferably 24. Also, it is preferable, though not necessary, that thefilaments terminate at the same height M relative to the pad 32.

Another embodiment of the pad 32 and attaching member 30 is depicted inFIG. 16. In this embodiment, resilient filaments 40 extend outward froma position where pad 32 attaches to member 30, at an acute anglerelative to the surface of pad 32. Any acute angle relative to thesurface will operate to resist relative movement of an occluded vessel,the preferred angle being 45 degrees.

FIGS. 16-18A depict an embodiment of a particular arrangement ofresilient filaments extending from between pad 32 and member 30 in twosets, one on each side of pad 32. Each set of filaments is organizedinto two intersecting groups. The filaments of both groups extend frombetween pad 32 and member 30 along a single plane. The filaments of eachgroup are oriented parallel to one another and at an angle relative tothe filaments of the other group. The preferred angle is a right angle.The planes defined by each set of filaments are oriented at an angle Lrelative to the surface of pad 32. The preferred angle L is between 45to 90 degrees, and is most preferably 45 degrees. This arrangement offilaments, when engaged with a vessel, will resist movement of thevessel in either direction relative to the length of the pad. When angleL is less than 90 degrees, the arrangement will also resist movement ofan engaged vessel in a direction transverse to the length of the pad.

As depicted in FIG. 18A, the distal ends of the filaments terminate at aposition above the surface of pad 32. In an alternative embodimentdepicted in FIG. 18C, the filaments terminate at a position below thesurface of pad 32. In the preferred embodiment, the filaments terminateat a position slightly above the surface of pad 32. It is alsopreferable, although not necessary that the filaments terminate at thesame height relative to the surface of pad 32.

In the embodiment depicted in FIG. 18A, the filaments 40 are mountedbetween pad 32 and member 30 and extend outwardly on each side of pad32. In the preferred embodiment there shown, member 30 has a channelwith angled sides that accommodate the filaments 40. The pad 32 has abottom surface with a reciprocal shape to fit the channel of member 30.In alternative embodiments depicted in FIGS. 18B and 18C, member 30 hasa channel with perpendicular sides. In these embodiments, pad 32 has aflat bottom surface and the filaments 40 are again accommodated betweenthe bottom surface of pad 32 and the channel of member 30. In anotheralternative embodiment, as depicted in FIG. 18D, the pad is divided intoupper and lower portions 32 a and 32 b, and filaments 40 are mountedbetween the portions and extend outwardly on each side of the pad. Thelower portion 32 b preferably has a channel with angled sides forreceiving the filaments 40 and the upper portion 32 a, which has areciprocally-shaped bottom surface, as depicted in FIG. 18D.

The operation of the embodiment of the invention depicted in FIGS. 16-18is illustrated in FIG. 19. FIG. 19 illustrates upper and lower jaws 22and 24, and opposed members 30, 30 and opposed pads 32, 32 havingresilient members mounted therebetween, in partial engagement withvessel V. The filaments have engaged the vessel V, as have the resilientsurfaces of pads 32, 32 which have deflected to accommodate the vesselin atraumatic fashion. The abutment of some of the filaments against thevessel V creates a resistive force against movement of the vessel. Inthe alternative embodiment where the distal tips terminate below thesurface of the pads, the pads engage vessel V first and deflect untilthe filaments also engage the vessel V.

An alternative arrangement of filaments is depicted in FIGS. 20-22. Inthis embodiment, the filaments 40 are arranged in similar fashion to theembodiment depicted in FIG. 16. Two sets of filaments 40 extend fromeach side of the pad 32 and each set of filaments is organized into twogroups oriented in a single plane with the filaments in each grouporiented parallel to one another and at an angle to relative to thefilaments of the other group, the preferred angle being a right angle.The filaments themselves, however, are mounted, and extend from, thebase member 30 itself, as depicted in FIGS. 20-22. In the preferredembodiment, the distal tips of the filaments terminate at a positionabove the surface of pad 32. In alternative embodiments, the tipsterminate at a position even with or below the surface of the pad (see,e.g., FIG. 18C). The operation of this embodiment of the invention isdepicted in FIG. 23 and is essentially identical in operation to that ofthe embodiment described above and depicted in FIGS. 16-19.

An alternative embodiment to the above embodiments containing two orthree rows of resilient filaments is depicted in FIGS. 27 and 28. Inthis embodiment, three distinct regions, or strips, of multiple rows offibers 46 extend from pad 32 (having longitudinal and perpendicularaxes, X and Y, as described above for FIG. 10-15). Each region or stripcontains fibers that are oriented in the same general direction. Thethree distinct regions are oriented in similar fashion to the three rowsof resilient filaments depicted in FIGS. 10-12. The fibers can becomprised of, for example, a synthetic fur. The fibers are resilientenough to resist movement of a vessel that abuts against the tips of thefibers. This arrangement of fibers, when engaged with a vessel, willlikewise resist movement of the vessel relative to pad 32 in eitherdirection along perpendicular axis Y of pad 32, and will also resistmovement of the vessel in one of two directions along longitudinal axisX. The preferred method of making this embodiment of the invention is toglue or otherwise adhere resilient filaments to a suitable backingmaterial, which is then secured to pad 32.

Manufacture of Resilient Filaments and Pads

The manufacture of resilient filaments and pads according to theinvention can be accomplished in many ways, as will be apparent to oneskilled in the art. One method of manufacture is illustrated in FIGS.24-26. As shown therein, filaments are secured in particularorientations along spines 60, 62 and 64. These spines are arranged ininterlocking fashion, as shown in FIG. 25, and then embedded into pad32, as depicted in FIG. 26. In the preferred method, the arranged spines60, 62 and 64 are secured in a mold, which is then filled with liquidinjection moldable silicone or silicone foam, and the silicone isallowed to cure to form a pad 32 around the filaments.

The embodiments of the invention described above and depicted in FIGS.16-23 can be manufactured using a plastic weave, such as a nylon mesh ora polyester or polypropylene braid. The plastic weave is comprised offilaments useful in the present invention. The filaments of the weaveextend at angles relative to one another. A cylindrical sleeve of theweave is cut in half and one portion is heat treated in a mold to shapethe weave into a form that will fit into the channel portion of member30 as described above and depicted in FIGS. 18A-18C. The treated portionof the weave is then secured in the channel portion of member 30,preferably using an adhesive, together with pad 32. As described above,the pad itself is comprised of resilient material, preferably liquidinjection moldable silicone or silicone foam. In an alternativemanufacturing method, the pad 32 is placed within a cylindrical ortubular sleeve of the weave and both are bonded to member 30. The weaveis then cut along its axis at or near the surface of pad 32.

In the preferred method, the pad 112 is placed within the sleeve 120, asdepicted in FIGS. 34A-34B. The two ends of the sleeve are then pulled inopposite directions, thereby tightening the sleeve against the pad, asshown in FIGS. 35A-35B. The sleeve 120, pad 112, and base member 110 arethen bonded or otherwise secured together, as depicted in FIGS. 36A-36B.An adhesive such as cyanoacrylate, for example, LOCTITE 406, can be usedto bond sleeve 120, pad 112, and base member 110 together. Excessportions of sleeve 120 extending beyond the ends of the pad 112 are thenremoved, resulting in pad 112 having a portion of sleeve 120 coveringits surface, as depicted in FIG. 37. The weave can then be cutlongitudinally, for example, along axis line O as depicted in FIG. 38A.Once cut, the resilient filaments 122 of the weave release and extendupward at acute angles relative to the surface of pad 112, as shown inFIG. 38B. In a variation of this method, the pad 112 can be placedwithin the sleeve 120, one side of the sleeve can be secured to the pad,and the sleeve can be cut longitudinally along the side generallyopposite the secured side prior to securing the sleeve-pad assembly tothe base member 110. In either case., the result is a pad according tothe invention. In this manufacturing method, the most preferred materialfor the pad 112 is a 40 durometer urethane or extruded vinyl foam andthe most preferred material for the sleeve 120 is a polypropylene braid.In the embodiment depicted in FIG. 38D, the filaments 122 extend outwardat an angle P from vertical relative to the surface of the pad 112 andterminate at a height above the surface of the pad. The filaments canalso extend upward in a generally vertical direction relative to thesurface of the pad 112, as shown in the embodiment depicted in FIG. 38C.

Surgical Retractors and Stabilizers

FIG. 29 is a Weitlaner surgical retractor comprising a pair of opposedretracting arms 82 and 84 hinged together by pin 80. The distal ends ofthe retracting arms 86 and 88 terminate in retracting fingers 90, 90.The proximal ends of the arms terminate in finger and thumb rings 72 and74 that provide for manual operation of the retracting arms by asurgeon. The proximal ends of the arms also carry an arcuate rack 78 andlocking pawl 76 having interlocking ratchet teeth which engage to secureretracting arms 86 and 88 in an open position when retracting tissue ata surgical incision site.

The gripping elements of the retractor comprise base members 92 havingresilient filaments that extend from the surface of the base members 92at acute angles. Each base member 92 is securable to retracting fingers90. As shown in FIG. 30, base member 92 contains apertures 94 which areadapted to receive retracting fingers 90 formed on the arms 86, 88. Asshown in FIG. 31, each base member 92 itself has a distal edge 96 and aproximal edge 98.

As is the case with the surgical clamp discussed above, resilientfilaments of base member 92 are comprised of a durable yet flexiblematerial, such as nylon or polyester. The filaments cannot be so rigidthat they puncture or otherwise traumatize the retracted tissue, butthey must be of a strength and resiliency such that they resist a forcein a direction opposed to the orientation of the filaments. Theeffective length of the filaments will depend on the length to diameterratio of the filaments. Filaments that are too short and wide maypuncture or traumatize the retracted tissue, whereas filaments too longand narrow may fold over upon themselves when a force is applied andwill be unable to restrict relative movement of the retracted tissue.The preferred length of the filaments is 0.030 to 0.075 inches, mostpreferably 0.060 inches. The preferred diameter of the filaments is0.005 to 0.012 inches, preferably 0.007 inches. Wider filaments can beused, provided they are sufficiently flexible. The ends or tips of thefilaments themselves can comprise a variety of shapes, as depicted inFIGS. 32 and 33. For example, filament 101 has a rounded tip, filament102 has an angled-cut tip, filament 103 has a blunt-cut tip, filament104 has a pointed tip, and filament 105 has a semi-rounded tip. Also,the filaments can be cylindrical 101-103, semi-cylindrical 105, orcontain three sides 104 or more. The preferred filament is cylindricalwith a rounded tip, as exemplified by filament 101.

The surface of base member 92 can be of a resilient material, preferablysilicone. The most preferred composition of the surface of base member92 is two part silicone of less than a 20 durometer, liquid injectionmoldable (GE 6040) or a silicone foam such as GE RTF762.

In the embodiment shown in FIGS. 29-31, some of the resilient filaments,comprised of resilient filaments 48, are oriented to resist movement ofretracted tissue T relative to the base member 92 in the direction ofdistal edge 96. The surface of base member 92 defines a plane containingtwo axes, an axis X running the length of the base member 92(longitudinal axis) and an axis Y oriented perpendicular to the axis X(perpendicular axis). A third axis Z intersects the plane in anorientation normal to the plane (normal axis). Resilient filaments 48are oriented at an acute angle K from the surface of base member 92 in aplane formed by perpendicular axis Y and normal axis Z. Additionalresilient filaments, comprised of resilient filaments 49, are orientedat acute angles J1 and J2 from the surface of base member 92 in a planeformed by longitudinal axis X and normal axis Z. This arrangement ofresilient filaments, when engaged with retracted tissue, will resistmovement of the tissue relative to the surface of base member 92 ineither direction along longitudinal axis X, and will also resistmovement of the tissue relative to the base member 92 alongperpendicular axis Y in the direction towards distal edge 96.

In the preferred embodiment, the angles J1, J2, and K are between 30-60degrees, most preferably approximately 45 degrees, and the number ofrows of resilient filaments is 10. It is preferable, though notnecessary, that the filaments terminate at the same height N relative tothe surface 92.

In an alternative embodiment of the invention, FIGS. 39-40 show aRichardson surgical retractor 160 comprising a handle 162, arm 164 andretracting blade 168 for retracting tissue at an incision site. Theretracting blade 168 has a resilient pad 170 on the retracting surfaceand resilient filaments 172 according to the invention that extend fromthe pad surface at acute angles. Another embodiment of the invention isdepicted in FIGS. 41-42, which shows a Balfour surgical retractor 180.This retractor has particular use in retracting tissue at an abdominalincision. The retractor 180 has lateral blades 181 and 182 fixed to arms183 and 184 respectively. Arms 183 and 184 are in turn mounted onparallel bars 185 and 186, with arm 183 being movable toward and awayfrom arm 184. Center blade 194 is fixed to arm 196, which is moveablymounted on bars 185 and 186 for movement of center blade 194 indirections perpendicular to the bars 185 and 186. Center blade 194 has aresilient pad 190 on the retracting surface and resilient filaments 192according to the invention that extend from the pad surface at acuteangles.

A surgical stabilizer according to the invention is shown in FIGS.43-45. The stabilizer 200 includes bar 202 that is pivotally coupled tomember 204. Member 204 is attached to the base of U-shaped foot member206. Arms 207 and 208 extend from the base of foot member 206 forengagement with and stabilization of body tissue or organs. Each arm 207and 208 includes a resilient pad 210 having resilient filaments 212extending therefrom at acute angles relative to the pad surface. In analternative embodiment, stabilizing members having resilient filamentscan be provided that are detachably secured to the arms, according toways described above with respect to surgical clamp pads or retractorbase members. In operation, foot member 206 is pressed against thetarget tissue or organ to stabilize or immobilize the tissue or organ.The resilient filaments of arms 207 and 208 engage the tissue or organand the abutment of the engaged filaments against the tissue or organprovides a resistive force that opposes movement of the tissue or organrelative to the arms. This action increases the amount of tractionapplied by the stabilizer to the stabilized tissue or organ.

FIG. 45 depicts stabilizer 200 in operation to immobilize a patient'sbeating heart in order to perform bypass surgery. Access to the heart isprovided by operation of rib spreader 220 that includes base member 226,fixed member 222 and moveable member 223 which is moveable toward andaway from fixed member 222 along base member 226. Rib spreading arms 224and 225 are secured to members 222 and 223, respectively. The arms 224and 225 are inserted into an incision and between two adjacent ribs overthe heart. Using conventional means not shown, arm 225 and member 223are moved away from arm 224 and member 222, thereby spreading apart theribs and providing access to the heart and surrounding tissues. Arms 224and 225 are secured in a fixed spaced apart relationship by thetightening of tumscrew 228 down onto a channel formed in base member226. Stabilizer 200 is then positioned to impart pressure against theheart to hold it in an immobilized position while it continues beating.The stabilizer 200 is fixed in pressure-bearing position by means offastener 214 that secures stabilizer bar 202 against base member 226.The secured stabilizer keeps that portion of the heart between arms 207and 208 adequately immobilized to allow graft procedures, includinganastomosis, to be effectively performed. At the same time, the improvedtraction provided by the resilient filaments that engage the heartfurther prevent shifting or movement of the heart, yet do so inatraumatic fashion.

Although only certain embodiments have been illustrated and described,those having ordinary skill in the art will understand that theinvention is not intended to be limited to the specifics of theseembodiments, but rather is defined by the accompanying claims.

We claim:
 1. A clamping member for attachment to a jaw of a surgicalclamp comprising: a means for attaching the member to the jaw; and aclamp pad having a surface, said clamp pad having resilient filamentsextending therefrom at an acute angle relative to said surface forengagement with a vessel or other tissue, said filaments terminating infree distal ends for abutment against a vessel or other tissue engagedby the clamp to resist relative movement between the clamp pad and thevessel or other tissue.
 2. A clamping member according to claim 1wherein said resilient filaments extend from said surface.
 3. A clampingmember according to claim 1 wherein said filaments are resilientlydeflectable to cushion a vessel or other tissue engaged thereby.
 4. Aclamping member according to claim 1 wherein the filaments aremonofilament and generally rectilinear.
 5. A clamping member accordingto claim 4 wherein the filaments have a length between 0.030 to 0.075inches and a diameter between 0.005 to 0.012 inches.
 6. A clampingmember according to claim 4 wherein the filaments are cylindrical.
 7. Aclamping member according to claim 4 wherein the filaments have at leastthree sides.
 8. A clamping member according to claim 4 wherein thefilaments have tip shapes, said tip shapes selected from the groupconsisting of rounded, semi-rounded, angled-cut, blunt-cut or pointed.9. A clamping member according to claim 8 wherein said tip shapes arerounded.
 10. A clamping member according to claim 1 wherein saidresilient filaments extend from said surface and wherein said surfacehas a first end and a second end and the filaments extend in directionswhich resist movement of a vessel or other tissue engaged therebytowards said first end of the surface.
 11. A clamping member accordingto claim 1 wherein said resilient filaments extend from said surface andwherein said surface has a first end, a second end, and a lengththerebetween, and the filaments extend in directions which resistmovement of a vessel or other tissue engaged thereby along a directiontransverse to said length.
 12. A clamping member according to claim 10wherein the surface has a length, and wherein the surface furtherdefines a plane, the plane having a longitudinal axis oriented parallelto the length of the surface, and a normal axis extendingperpendicularly from the plane, and wherein a group of said filamentsextends at an angle from the surface in a plane defined by thelongitudinal axis and the normal axis.
 13. The clamping member of claim12 wherein said angle is between 30 to 60 degrees.
 14. A clamping memberaccording to claim 10 wherein the surface has a length, and wherein thesurface further defines a plane, the plane having a longitudinal axisoriented parallel to the length of the surface, a perpendicular axiswithin the plane oriented perpendicular to the longitudinal axis, and anormal axis extending from the plane oriented perpendicular to both thelongitudinal axis and the perpendicular axis, and wherein a first groupof said filaments extends at a first angle from the surface in a firstplane defined by the longitudinal axis and the normal axis, and a secondgroup of said filaments extends at a second angle from the surface in asecond plane defined by the perpendicular axis and the normal axis. 15.The clamping member of claim 14 wherein said first and second angles arebetween 30 to 60 degrees.
 16. A clamping member according to claim 14wherein a third group of said filaments extends at a third angle fromthe surface in a third plane defined by the perpendicular axis and thenormal axis in a direction opposed to the direction of said second oneor more of said filaments relative to the perpendicular axis.
 17. Theclamping member of claim 16 wherein said third angle is between 30 to 60degrees.
 18. A clamping member of claim 10 wherein the surface has alength, and wherein the surface further defines a plane, the planehaving a longitudinal axis oriented parallel to the length of thesurface, a perpendicular axis within the plane oriented perpendicular tothe longitudinal axis, and a normal axis extending from the planeoriented perpendicular to both the longitudinal axis and theperpendicular axis, and wherein a first group of said filaments extendsat a first angle from the surface in a first plane defined by the normalaxis and a first axis parallel to the plane of the surface, and a secondgroup of said filaments extends at a second angle from the surface in asecond plane defined by the normal axis and a second axis parallel tothe plane of the surface, and said first axis and said second axisintersect to form an intersection angle less than 180 degrees.
 19. Theclamping member of claim 18 wherein said first and second angles arebetween 30 to 60 degrees.
 20. A clamping member of claim 2 wherein saidsurface comprises resiliently deflectable material.
 21. A clampingmember of claim 20 wherein said resiliently deflectable materialcomprises silicone.
 22. A clamping member according to claim 1 whereinsaid clamp pad has a first end and a second end and said filamentsextend in directions which resist movement of a vessel or other tissueengaged thereby towards both said first and second ends.
 23. A clampingmember according to claim 22 wherein said surface comprises aresiliently deflectable material for engagement with said vessel orother tissue when said jaws are moved toward one another.
 24. A clampingmember according to claim 23 wherein said surface comprises silicone.25. A clamping member according to claim 23 wherein said filamentscomprise a first group and a second group of filaments, said first grouphaving filaments oriented parallel to one another and said second grouphaving filaments oriented parallel to one another and at an anglerelative to the filaments of said first group.
 26. A clamping memberaccording to claim 25 wherein said angle between filaments of said firstand second groups is a right angle.
 27. A clamping member according toclaim 25 wherein said surface defines a first plane and said first andsecond groups of filaments define a second plane, and wherein said firstand second planes intersect to form an angle between 45-90 degrees. 28.A clamping member according to claim 27 wherein said angle ofintersection is 45 degrees.
 29. A clamping member according to claim 27wherein said filaments terminate at a position below said first plane.30. A clamping member according to claim 27 wherein said filamentsterminate at a position above said first plane.
 31. A clamping memberaccording to claim 25 wherein said means is a rigid member and saidfilaments are mounted between the rigid member and said clamp pad.
 32. Aclamping member according to claim 25 wherein said means is a rigidmember and said filaments are mounted on the rigid member.
 33. Asurgical clamp according to claim 25 wherein said clamp pad has an upperand a lower portion and said filaments are mounted between the upper andlower portions.
 34. A clamping member for attachment to a jaw of asurgical clamp comprising: a means for attaching the member to the jaw;and a clamp pad having a surface, said clamp pad having resilientfilaments extending from said surface at an acute angle relative theretofor engagement with a vessel or other tissue, said filaments terminatingin free distal ends for abutment against a vessel or other tissueengaged by the clamp to resist relative movement between the clamp padand the vessel or other tissue, wherein said filaments are arranged inone or more rows generally parallel to the pad length, and wherein saidone or more rows includes a first row having filaments extending in aplane normal to the pad surface and parallel to the pad length, and asecond row having filaments extending in a plane at an oblique angle tothe pad surface.
 35. A clamping member according to claim 21 whereinsaid filaments are resiliently deflectable to cushion a vessel or othertissue engaged thereby.
 36. A clamping member according to claim 34wherein said filaments resist movement of a vessel or other tissueengaged thereby along a direction parallel to the pad length.
 37. Aclamping member according to claim 34 wherein said filaments resistmovement of a vessel or other tissue engaged thereby along a directiontransverse to the pad length.
 38. A clamping member for attachment to ajaw of a surgical clamp comprising: a base member for attaching theclamping member to the clamp jaw; and a clamp pad having a surface forengagement with a vessel or other tissue, wherein resilient filamentsextend from said base member to a position above said surface and at anacute angle relative to said surface for engagement with a vessel orother tissue, said filaments terminating in free distal ends forabutment against a vessel or other tissue engaged by the clamp to resistrelative movement between the clamp pad and the vessel or other tissue.39. A clamping member according to claim 38 wherein said filamentsresist movement of a vessel or other tissue engaged thereby alongdirections parallel to the pad length.
 40. The clamping member of claim38 wherein said filaments comprise first and second groups of filaments,said first group having filaments oriented parallel to one another andsaid second group having filaments oriented parallel to one another.